Geronimo! RC Paratroopers

Model Airplane News, Feb 2005 by Yarrish, Gerry

AT LAST-AN AUTHENTIC-LOOKING DEPLOYMENT METHOD

AMONG THE MORE FAMOUS SCENES of WW II was that of the Douglas C-47 Skytrain pouring Army paratroopers over battlefields on D-Day. Countless G.I.s arrived under those big, billowing silk chutes. It's little wonder, then, that dropping miniature-scale paratroopers out of RC airplanes has been tried innumerable times! But this function has never seemed to look quite right-that is, until the recent U.S. Scale Masters Championships in Gardner, KS.

Competing with a big, Ziroli-designed C-47A, Greg Hahn of New Castle, IN, figured out that for a scale paratrooper deployment to look right, the G.I.s had to "jump" out of the airplane with a slight delay between each one. So with some plywood, springs and dowels, Greg came up with a device that would eject each paratrooper sequentially with the flick of a single switch.

Using old, junk-drawer servos wired to some microswitches, the device is little more than a plywood box with six separate compartments that each contain a spring-loaded dowel plunger held in the firing position by a pull-pin. Each pin is attached to its own microswitch-driven servo. The servos are all powered by separate battery packs but are not controlled by the radio! A separate servo controlled by the radio opens the ejection box's door and then hits a microswitch to activate the first servo in the firing sequence. After it pulls the first pin, the servo then trips the microswitch for the next servo, and the operation is repeated in a cascading fashion until all six paratroopers have exited the aircraft.

As the airplane makes its pass at about 2/3 throttle, the delay between each servo produces a spacing of about 8 feet between each paratrooper. The result is a very scale, correct-looking deployment that flight judges always score well. I know it was only my imagination, but as the C-47 made its pass, I could have sworn I heard a faraway voice yell "Geronimo!"